The eosinophil chemotactic factor of anaphylaxis (ECF-A) was discovered in 1971 as a mediator released during immediate hypersensitivity reactions in guinea pig (Kay et al., J. Exp. Med. 133, 602 [1971]) and human (Kay and Austen, J. Immunol. 107, 399 [1971]) lung slices. ECF-A was subsequently recognized to be present totally preformed in rat mast cells in association with the granules (Wasserman et al., J. Immunol. 112, 351 [1974]), human leukemic basophils (Lewis et al., J. Immunol. 114, 87 [1975]) and mast cell-rich tissues such as human lung and nasal polyps (Kaliner et al., New Eng. J. Med. 289, 277 [1973]).
The activities of ECF-A are preferentially directed to eosinophils as compared to neutrophil and mononuclear leukocytes and include chemotaxis, chemotactic deactivation, stimulation of the hexose monophosphate shunt and release of granular enzymes.
Due to the fact that only extremely small quantities of ECF-A are present either preformed or after release from sensitized tissue, it has not heretofore been possible to purify sufficient material for structural characterization. Moreover, since partially purified preparations of ECF-A contain histamine and other peptidic materials which produce other pharmacological effects, it has not been possible to accurately assess the spectrum of activities or potency of ECF-A or to employ this material as a therapeutic agent.